Intraoperative Electrode Localization Tool

Temporary use of cortical subdural electrodes during deep brain stimulation (DBS) lead implantation surgery allows for the study of cortical local field potentials (LFP) recorded simultaneously with LFP and/or single unit recordings from the target structure. However, only two-dimensional fluoroscopic imaging is readily available during these surgeries at many academic DBS centers.

To accurately localize such cortical electrodes in three dimensions, we developed a novel tool that uses information from both 3-D skull and brain reconstructions. Pre-operative CT and post-operative MRI are manually aligned with the fluoroscopic image using identifiable landmarks such as the outline of the skull, orbital roofs, and stereotactic frame pin tips. After alignment, users can register the location of each electrode in brain space by simply clicking on it on the fluoroscopic image.

The full localization tool, as a set of MATLAB scripts, can be downloaded below. Additionally, a tool simulator has been provided with a sample subject’s data already preloaded, including results of movement related high frequency activity analysis from a simple handgrip task. These results can be mapped to the cortex based upon the registered electrode locations. This sample is available both as a set of MATLAB scripts and as a compiled, executable file for users who don’t have MATLAB downloaded on their system.